Playback system



C- 5, 1965 J. P. Woons Erm. 3,210,770

PLAYBACK SYSTEM 4 Sheets-Sheet original File'd'March 51. 1961 INVENTORS Joh/1 l? Woods v Tom Fricke# Jn ATTEST.

James 'K you/(sings ATTORNEY n PLAYBACK SYSTEM Original Filed March 31. 1961 4 Sheets-Sheet` 3 KTM .93 N 3 v u. u.. u. u. LL-

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D! N m53 s- Ll.. L.

...INVENTORS Arron/wr Ot. 5, 1965` J. P. wooDs l-:TAL 3,210,770

PLAYBACK SYSTEM original Filed March 51. 1961 4 Sheets-Sheet 4' owm 9 A!!! 5L of@ H m9 (308m ml, :E Sllf as? zu@ 0.@

INVENTORS WOOdS John l? Tam Printer( Jn Edv/'n 5'. Nelfze/ BY Will/'am M. Mull/nys James K Agn; ATTORNEY interpretation. a v v l Magnetic recording has been known and utilized for many years; and since World War II, the use of magnetic recording in geophysical exploration has increased at an tempt to furnish a on to its next location` PLAYBACK SYSTEM John P. Woods, Dallas, Tom Prickett, Jr., Richardson, and Edwin B. Neitzel, Dallas, Tex., assignors to The Atlantic Refining Company, Philadelphia, Pa., a cor-v Continuation of i application Ser. No. v99,858, Mar. 3l, 1961. This application Feb. 25, 1964, Ser. No. 348,322

Claims. (Cl. 346-33) 'poration of Pennsylvania The present' application is a continuation of our copending application, serial No. 99,858, filed March 31,A`

"1961, now abandoned.

This invention relates to a'recording system suitable .foruse with a field or office type recorder or computer.

More specifically; theinvention relates to an improved automatic signal switching and transducer indexing sys-y tem designed to reproduce records in accordance with requirements peculiar to hydrocarbon exploration and impressive rate. However, in spite of the rapid increase in the use of magnetic recording in this field, to date nosatisfactory recorder playback combination capable of i .j meeting the peculiar requirements of hydrocarbon exploration has been invented. In the seismic field of geophysical exploration numerous devices are used in an atl field recorderoperator with a high speed, economical, and satisfactory visual check or monitoring apparatus for. determining the success of the magnetic. recorder in capturing seismic reflections in read-` able form. Withv a proper monitoring apparatus theoperator ca n quickly determine after each firing if the recordings arer satisfactory. If one or more of the chanvnels are not recorded in a readable form, a second shot or series of shots vcan be fired before the party moves By using the proper monitoring means, the party is able to save thousands of dollars in time, explosives, etc.,- that would normally be required or monitoring systems are used today in conjunction with magnetic recorders tocheck the'readability of recorded signals. Photographic oscillographs, fluorescent screens,

and various types of recording pen systems are common devices for providing a visual check of magnetic recording. Probably, one of the most satisfactory answers to :the )basic monitoring requirement is found in United vStates Patent No. 2,803,515.

This patent discloses a magnetic field recorder and playback combination that simultaneuosly records a number of seismic signals and thereafter, for monitoring purposes, sequentially, chan-v nel by channel, transcribes the recorded seismic signals on Teledeltos-paper. The device may be made to repeat the reproduction of any channel by actuating a repeat Aswitch lor may be made to return to the start position by actuating a vmanual reset button. Although the patent surveyed.

ing'drurn is approximately y8 to l2 inches in length or with a central office computer` where the drum is from 4 to S feet in length. This extreme variation in drum length imposes severe requirements of flexibility on the switching system as well as on the pen indexing portion Aof the playback combination.

First, with reference to the control means vrequirements mentioned above, it is highly desirable in all hydrocarbon exploration and interpretation operations, and man-I datory in some, that the apparatus be versatile enough to'4 (1) be able to select the recorded channels to be transcribed, (2) be able to adjust the width of the transcribed channels, (3) be able to adjust the distance between thev edge of the transcribing medium and the first transcribed channel,I (4) be able to provide a center gap or an area on the transcribing medium for noting seismic information and computations, (5) be able to adjust the center gap as to width and location, and (6) be able to start andstop the transcribing apparatus at any desired location.. The above versatility is utilized, all or in part, either in.- the field to aid the monitoring operations or in an installation to' aid record interpretation operations. l The operator in the field, in addition to utilizing themonitoring and control means to check recording quality, uses it to de-` termine; the type and quality of filtering required to overcome noise and interference inherent in the area being The magnetic channels that he desires to `l monitor or lthe number of geophones used in the particular survey will, in most cases, dictate the recorded `in reshooting positions at'later dates. Various display provides a satisfactory basic field recording and playback y combination, it is not versatile enough to meet the overall requirements of hydrocarbon exploration. Since this type of exploration is highly specialized and complex,

the modified conventional type playback or transcribing system as discussed above is not satisfactory. Due to the peculiar requirements of this specialized type of exploration, a desirable playback apparatus, in'addition.

to affording a visual monitoring means, must also provvide some type of'control means designed to presentthe transcribed information in a manner suitable for the particular purpose for which the information is to be used.

Ideally, this apparatus should also be versatile enough to be used witheither a field recorder where the transcribchannels' to be transcribed, the width of the edge gapf' the width and location of the transcribed channels and the width and location of the center gap. The use of l such a lversatile vplayback system is even more essential when the magnetic recordings are utilized in a computer installation. Here, the playback system is used for such' operations as `transcribing new records received from the field, refiltering the new records, transcribing and v reltering for comparative purposes old records taken in the same area or similar areas, transcribing new orold logs made in the same area, and presenting desired combinations of the above'information on the same playback medium for correlation purposes. In accordance with the studies to be made, the different records to be used, andV the number of channels Vto be transcribed, the width of the edge gap, the width of the transcribed channel, and

the location and width of the center gap are determined. f

In addition to the above types of presentation, the playback system must also be able to change previously recorded exploration data into cross sections of the areas previously explored. v

' In summary, it is obvious that a playback system satisfactory for hydrocarbon exploration and interpretation purposes cannot be one limited to transcribing seismic data in a stereotype form. This is especially true sincev it is frequently desirable to transcribe seismic information, appropriately recorded well logging information, as

well as other types ofvexploration information, on the same medium so that visual or automatic correlations betweenth'e different information can bemade. Therefore, a satisfactory playback system must be versatile' enough (1) to accommodate itself to operate on various types of recorded information and (2) to transcribing the information in the form that will facilitate interpretating the particular information transcribed.

It is, therefore, an object of this invention to provide a versatile automatic playback system usable with either a field recorder or office computer and incorporating controls so that the transcription can be made in a form suitable to the interested partys needs.

Another object of the inventionis to provide an automatic palyback means capable of transcribing various types of previously recorded hydrocarbon exploration in- 3,210,770." ylravterrted Qct. 5, 1965v y l tem at the desired positions.

'matrix.

tem"'11, transcribing formation in a form best suited to facilitate interpretation of the information.

Another lobject of the invention is to provide a compact, transportable, and rugged playback unit capable of being utlized'either in the field or in an ofiice.

Another object of the invention is to provide a "sim.

plified playback system exhibiting a minimum of moving partsfand adapted to provide'fast accurate'records and dependable service under field conditions.

Another object of thcinvention is to provide a switching system with means to adjust the transcription channel widthfedge gap width and center gapyvidth, means to locate' the centerV gap and select thcdcsired `channels to be transcribed, and a means to start and stop the sysi FIGURE' 3c shows an alternate start and reset circuit for use with `the matrix shown in 3a.Y

FIGURE 4 is a circuitdiagram of `a block-diagram shown in FIGURE 3.

.Briefly`stat`ed, the' preferred form .of the linvention is portion of rthe "concerned with an automatic playback system in'which a switching means connecting magnetic read heads to a `transcribing pen indexing means allows settings to be made to control the 'form andsequence offtranscription. The

novelswitching matrix and control circuitry, as' well asv 'the indexing device, aredesigned vfor minimum physical wear and simplicity of operation so that they can function .in the field' 'or in the office with a minimum of maintenance.

.Within the broad statements of the invention as given above, there are numerous combinations and subcombination's of Vapparatus whichare in themselves novel and which will be so recognized as the inventions are described in detail. r FIGURE 1 is a schematic diagram of one possible .combinationof applicants invention and conventional recording and transcribing devices. Applicants invention is shown as playback switching system 1, `playback' switching `control circuit, p'en indexing system 5, :mag-

netic recording drum 7, magnetic heads 9, detector syspen '13, pen amplifier '15, and transcribing drum 17.

Inajfurther and moredetailed description-of the invention reference'-will first be. made to each invent-ion in its broad application and then to some Aofits specific variations.

' Recorder switching system `and vcontrol circuit The basic function of the switching system'is toautomatically and lselectivelyconnect read and-write means sothat'previously recorded data are automatically transcribed as directed byyinstructions set in associatedcontrol means. The basic function of the control means is to command the 'indexing system to position ythe transc'ribing element so 'that it reproduces the data in a preselected manner'compatible with requirements peculiar to hydrocarbon exploration and interpretation activities. v4 The control means may-physically be a part of o r separrate from the switching system, as will be explained in the appropriate subheadings .to follow.

: FIGURE 1 discloses `an over-all recording 'and tran- 4 scribing system in which themajor components are shown in block form. Novel variations of the basic matrix 1 and control system 3 are shown'in FIGURES 2, 3-and 4. Components, circuits andfelements s'hownin lFIG- URES 2, 3 and 4 that are 4similarfto those 'shown' in FIGURE 1 are labeled withthesan'tenumbers. Playback switching matrix 1, FIGURE 1,l is shown as afnum- .berof ganged sequential'multicontactJswitchesv19, 21, '23 and 25. Multicontact .switch 19 connects4 magnetic.

vheads 9 to detector system 11.

Multicontact Aswitch 21 connects an voutputof detector 11"to the input of'pen amplifier 15. Multicontact switch23- connects a voltage source 27 "through a resistor 'system v29 and control circuit 3'to the-input of .pen indexing means 5. "The rpen index-may include .a se'rVO'mcChaniSm, a motor .drive mcchanism,ror a simple circuit connected lto the device vdepending Yupon the type of pen' index used. -Switchf25 is `connectedto ramp switch 31 4onmagnetic recording d rum 7 .andy is'designed to r.be pulsed byleach revolution ofthe drum. Eachtime `switch25 isrpulsed by switch 31, `the rnext succeeding 'contact on "the lswitch is closed,

thus-moving .25 and its ganged 'switches `A19, 21 ,and '23-to vtheir next succeeding contacts.' Switch 25 containsreceptacles "33 '-for start vpatch plug 35, center gap 'plug 37 and stop plug 39.

bridges vthe undesired switch contacts and vlocates ythe desired center gap von transcribe drum 17.

Control circuit 3 converts preset "transcribing instructions into proper command voltagesfor the pen 'index system. As will be vdetailed'in'the pen index ,'subheading,

the type of-penindex'used determines the type of control 'circuit'required Control circuit 3, FIGURE 2,'produces a command voltage suitable for operating a servo-'driven pen,r as shown kin lFIGURE 5. Control circuit 3, FIG- I URE 4, produces an error voltage-suitable `to operate a conventional servo-driven lead screw index. If ak pulse type indexing device, is jused, the control system can vbe asimple circuit 'connecting a pulse circuit, ysuch as switch 23', FIGURE 1, to thepen index.l Of course,

necessary relays and patch cords connections or the like are required, as described hereinafter, to avoidthe un` desired channels.

Operation ofthe playback switchingmatrix jand'control circuit in FIGURE 1 is as follows. Prior'to the playback, the desired transcribe instructions are set Vin'the r`control circuit. `Start plug 35, ycenter gap plug 37, and'- stop plug'39 are placed in the appropriate'receptacles 33.

vT he plug positions determine the magnetic channels to be replayed and vtheposition `of `the ,center gap, as will ybe described in Vmore detail `in the matrix subheadings'. Any

or all of the above instructions may be varied 'aftereach transcribing operation or may .fbe retained as long` as appropriate.

After the'r desired vadjustments have been Imade on the control circuit and-patchv board, the system isrthen ready for' a' yfire'-record-transcribe sequence or a transcribe sequence, depending on the purpose ofthe 'playbac'k'and the type recorder ybeing used. Assuming that' the desired 'inf formation-is already recorded on drumv 7, the playback sequence is as follows. The `proper'magnetic'fhead'9 is selected tby the positionof switch 19-which in turn is determined by switchr 25 and -the receptacle 33 -in which' start plug' 35 is inserted. The magnetically recorded intelligence under'the selected head is readI out kand sent through detector systems 11, vswitch` '21, playback vampli- -er 15 .to playback 'pen k13, where it is transcribed on a kmedium'mountedfon `drum`17. `During this operation, -switch .23, which was simultaneously positioned along with 19 and'21,'connects'D.C. voltage 27 to control -circuit 3 where a command voltage is developed. This command vvoltage causes pen `indexfS to'zposition playback pen 13 over an Vappropriate transcribe `channel on drum' 17. As playback pen 13 completes'the transcription of the selected magnetic channel, 'drum' 7 completes a As will be explained indetail hereinafter, Vthe proper connection of 'plugs vand receptacles switching and control circuits and ving 41.

d .relay 57. Contacts oppositely poled diodes 59. Contacts 51 are connected between` two adjacent diode groups 59 to their respective single revolution causing pen shift ramp switch 31 to close producing a-D.C. pulse. The D.C. pulse causes switch 25 to move to its next succeeding contact. If the succeeding contact is bridged by center gap plug 29, the next selected contact is activated. Since switch 25 is ganged to 19,` 21 and '23, the appropriate contact on each switch is activated andthe recorded information from the next' selected .magnetic head is transcribed on drum 17. This operation is repeated until the contact on switch 25, selected by stop plug 39, is energized. At that time, the D.C.xpulse from the recording drum is short-circuited to ground, all switch contacts are cleared, and the playback sequence is complete.

Relay-diode switching matrix Reference is now made to FIGURE 2 where the novel relay-diode switching matrix and control lcircuit are shown in their preferred use as part ofv a seismic field recorder. Of course, the switching matrix and control circuit are not limited to this use and can be utilized with equal facility in other recorders and computer systems. The drawing is an exaggerated form to emphasize the I yet show a working computer elements. indicate that certain arrangement withl conventional Dotted lines between components elements not essential to the invention have been omitted.

For the sake vof simplicity, timing and time break heads are not shown; however, with the information disclosed in FIGURE 2, modifications necessary to produce conventional seismic timingv lines are obvious to one skilled in the art.

The basic operation ofthe system shown in FIGURE 2 can be generally the same as FIGURE l; however, the

control system and the switching matrix incorporate many additional novel features, such as will be appreciated from the description to follow. v

` The switching matrix consists of a preselected square or rectangular array of hermetically sealed relays, their contacts and oppositely poled diodes. The number of relays, .relay contacts and the configuration'of the array are determined by the switching operations to b'e perl i'formed and the number of information channels to .be

handled. For identification purposes, .in veach row of the array bear thejsame similar elements numbers. Relay windings 41 are arranged in a horizontal row and relay contacts 43, 45, 47, 49 and 51 extend in vertical columns above their respective relay windings.l contacts is opened or closed by a plurality of ganged rotor arms 53 controlled by their respective relay windrow of the array is conf Contact 43 in each nected to an individual magnetic head 9 located on drum 7. Contacts 45 are connected to detector system 11.

Contacts 47 are connected to contact 55 in playback start 49 are connected to their respective,

relay winding 41, Control circuit 61, 63, and 65, 69 and 71.

and to its associated receptacle 33.v 3 includes a plurality of potentiometers relay 67 and two D C. voltage sources Playback control switch 57 includes relay winding 73 operating ganged rotor arms 75 yand contacts 55, 77, 79, 8l, 83 and 85. Pen index 5 is connected through dotted vline connection to potentiometer 61. Pen s hift ramp switch 31 on drum 17 is connected through dottedline connection to the'ganged rotor arm for contact 77. Relay 67, control circuit 3, is connected to center-gap patch plug 37 and to stop relay 87.

Potentiometer 61 which is connected to pen index'S and through contact 55 of switch 57 to contact 47 in the pen locationcircuit row of the switching matrix, acts as Each column ofv voltage until the contacts determines the center gap location on drum 17. Potentiometer 65 is connected between D C. source 71, ground and potentiometers 61 and justs the width of the edge 63. This potentiometer adgap of the distance between the edge of the transcribing medium and the first channel transcribed. Briefly stated, potentiometer 61 acts as a.

voltages from potentiometers 63 and 65 and from the selected pen location contact 47 are attenuated in equal proportions by the gain or summing potentiometer 61. Potentiometer 65 and the selected contact 47 always determine portions of the command voltages that are applied to index 5; ter gap potentiometer 63 is not applied as part of the command voltage until the selectedcontact 51 is reached. is selected by inserting center gap plug 37 into theselected When the selected contacts winding is activated, the addition voltage drop across potentiometer 63 is added to the command voltage resulting in an additional movementfof the pen index means 5 and a resulting gap between the selected channels on 17. D.C. source 69 con- A nected to relay 67, control circuit 3, acts vas a holding voltage after the relay in which center plug 37 has been vinserted is deactivated. center gap voltage as a portion of the totalcommand 39, as will be explained in detail hereinafter.

The complete operation of the relay-diode playback ymatrix and control circuit is as` follows. The desired transcribe channel width is set in potentiometer 61, the

center gap width is set in potentiometer 63 and the desired edge gap width is set iin-65. For purposes of illustration, start patch plug 35 is placed in the first receptable 33, the center gap plug and the stop patch plug are set in the desired receptacles 33. Playback control relay 57 is manually or automatically actuated as desired.

With this actuation, ganged rotors drop to their lower contacts. When contact 81 is closed, a negative 24 volt source is applied through switch 87 in the hold circuit, through start plug 35 to its receptacle 33. The negative vvoltage factuates the .first relay winding 41 causing its ganged rotors53 to close. With the activation of the first relay the corresponding read head 9 is activated and pen'index 5 is simultaneously commanded to position transcribe pen 13 toits appropriate channel on drum 17. The simultaneous actions are performed as follows. Ganged rotor arm 53 closes on contact 47. Since'contact 55, relay 57 is now open a negative pulse is sent through 'contact 47'and its associated rotor arm 53 to control circuit 3. The applied voltage passes through the summing network. producing an output voltage proportional to the settings on potentiometers 61 and 65. The command voltage is transmitted to the pen index which positions transcribe pen 13 according'to the command voltage. During the time the transcribe pen is being positioned, contact 43 which was also closed by 53, ac-

tivates the first `magnetic head 9 causingv it to read out .tive pulse is applied to the cathodes of the two oppositethe hold circuit, making them both ly poled diodes 59 in conductive with the result that the negative 24 volt hold voltage is passed through the diode to the next relay winding 41. The application of the negative voltage on the f next relay winding activates the relay closing its ganged however, the voltage drop across cen-v contacts receptable 33.'v

This .maintains the additional I 51 are deactivated by stop plugy I two such blocks are shown.

rotor arms 53 on its numbered contacts.- The circuit to the preceding relay isthen broken since the hold voltage is'no longer applied and its ganged rotor arms 53 move from the numbered contacts to the open posi- -tions. With `each revolution of drum 17, the next succeeding relay winding'41 or the next relay selected by the position of the center gap plug 37 is activated. As

' the next desired relay is' activated, the appropriate magnetic head 9 transmits the previously recorded information through detector 'circuit 11 to penamplitier 15 and playback pen 13. The detected, previously recorded information reaches pen 13 after the appropriatepen loca tion command voltage hasfbeen appliedv to pen index and playback pen 13 has been positioned over its new transcribe channel. When the relay windingl 41, in which stop patch plug 39 is inserted, is reached, the negative 24 volt hold current is short-circuited to ground; and all loit' the relaywindings 41 are de-energized.

v Counter-'transistor switching matrix nected to ground and whose collector is connected in parallel to plug receptacle 33 and resistor 173. "Re-v sistor 173 is connected in parallel tomagnetic head 9,

isolating capacitors 175 andu 177 and diode 179.. The

cathode of diode 179 iseonnected tothe input of de- A One end of diode 179 is-connected tothe intector 11'. put of detector 11. One end of resistor 181 is connected in parallel with receptacle 33 and diode 185 which is connected with its respective vresistor 183. The value of each resistor 183 is graduated according to the column conductor circuit to which itis immediately connected,

as will be explained in detail hereinafter.l The graduated resistors 183 are connected in series to control cirv cuit 3. D.C. source 187 is connected in parallel to re- Onepossible use of the novel preferred counter-tran-v sistor playbackswitching matrix and control circuit is Y `shown in FIGURES 3 and 4. In this variation, the recording drum systems and other circuitry not important to .the inventive concept have been omitted for purposes Y olsimplicity.y FIGURE 3a shows a portion'of the switcho ing lmatrix in'which the column conductors terminate at, oddnumbers 89 through 137. Although each column 4Referring now -to FIGURE 3a, the-counter-transistor playback switching matrix utilizes a square or rectangular array of horizontal conductors 141 and vertical conductors identified by their terminatingy points shown as oddnU'mbers y89 through 137. As in the previously described matrix, neithertheshape of the matrix nor the number of conductors used is important to the inventive concept. Row conductors 141 are connected to five transistorized binary counters or flip-ops l143 connected in cascade. Two succeeding row conductors are connected The upper output is zero volts, and the lower output is +12 volts.

- :The row conductors are also connected to preselected column conductors by 47K ehm resistors 145, shown in FIGURE 3b.' v These resistors are located and connected sothat, regardlessof-the output condition of the cascaded counters, the terminating point output of one column conductor is in the zero potential vcondition and the remainder of the terminatingpoint outputs are inthe plus volt condition.

Start circuit 147', FIGURE 3, includes counter 149 connectedto Hip-op 151 which in turn is connected to gate 153. A 400 c.p.s. oscillator 155 is connected'to gate 153y and. 153 is connected tothe-input of upper ip-llop 153 in sistors 181. l

For purposes o f illustration, control circuit 3,.FIG

URE 4, is adapted to operate a conventional servo-driven lead screw indexing system; however, theswitching matrix-is not limited to operating with this type of pen indexing system. The control circuit is constructed to present an error voltage to a servo index, not shown,

until a transcribing pen is positioned correctly. The basic components in the control circuit include width potentioml eter 189, center gap potentiometer 191, and edge gap poo tentiometer 193, synchronous chopper 195 and terminals 197 and 199. Terminal I197 is connected through a voltagedividernetwork made up of .potentiometers 189, 191

and 193 so as to presenta command voltage indicative p of the'desired transcribe: pen position. Terminal 199 is lconnectedlfto apen index position potentiometer,'not shown, and presents a voltage indicative of the actual position of the transcribing'pen. As pointed vout vheretofore, .each output resistor 183 is graduated in value depending vupon the terminating circuit 13 9 in which it is located.4 In operation, the selected circuit .139 produces an output current, determined by the graduated'resistor 183 through which it passes, that is applied to the volt-v age divided Inetwork madev up of potentiometers 189 and 1943.l The output' current applied to the' voltage divider network develops a command voltage at terminal 197 ini dicative of the desired position ofthe transcribe pen 13.

to the outputs-of each counter 143. Each counter has -two output voltages in the cleared condition.

Synchronous chopper 195' compare-s the voltage appearing at 197 and the penposition voltage appearing at 199 and transmits the' difference,` or the error voltage, to the servo. The servo responds to the error 4voltage in a conventional manner positioning pen 13,. FIGURE 1, until the voltage from the pen index potentiometer appearing at terminal 199 equals the voltage appearing at 197. As in the FIGURE 2 control circuit, the center gap voltage is not added -to the voltage network until the matrix switches to the columnconductor with thev receptacle 33, containmgthe -center gap patch plug. When this conductor is nected between detector system 11 and transcribing pen amplifier 15 for the purpose of routing thedetected sig-' i f nals linto a desired pre-transcription operation. For

the conductor array. Reset circuit 157 includes resistor l 159 and 161 and transistor 163. Output 165 of reset circuit 157 is connected to inputs 167 of Hip-flops 143. 'Start patch cord 35 is connected to counter 149 and stop patch cord 39 is connected to reset 157. For purposes of simplicity, center gap patch cord 37,` FIGURE l, is represented as switch 169 in control circuit 3, FIGURE 4.

Refer now to FIGURE 4 vwhich showsy a detailed schematic of block 139 together with its adjacent block 139 circuits, detector system 11 and control circuit 3. The` lower end of each column conductor shown in FIGURE 3 is connected to the similarly numbered base of a vtransistor 171 shown in FIGURE 4. Eachblock 11.39 circuit includes transistor 171 whose emit-ter is conpurpose'sof illustration, 'assume that a 1600 c.p.s.` timing signal followed by a seismic signal are to be detected and transcribed. The trace selector switch routs the timing signal to a divider circuit that reduces the timing signal to c.p.s. after which it is transcribed. When the switching matrix moves to the next channel so the seismic signal is read to the detector, selector 201 is simultaneously switched so the detected seismic signal is routed to the seismic lilter circuit before it is transcribed. Trace selector 201 can be a conventional transistor switching system and connected to the particular column conductor in the matrix sothat it-produces the described switching action.

Before discus-sing the complete operation of the switching matrixpand itscontrol circuit, shown in FIGURES 3 and 4, a brief study of the matrix clearing operation and circuit 91 operation is in order.

' pole, double throw toggle switc-hes 13b, vertical conductor dition.

' output of col-umn conductor 97 is changed to zero volts. The zero. volt condition pulses counter 149, causing gate 153 to close, thus maintaining the selected column conductor: output 97 in the start or zero potential condition for one drum revolution. As will be explained hereinafter, the receiptof a pulse after each drum revolution vcauses the next lower counter output in cascaded counters 143 to change to zero potential and by virtue ofthe row-column connections 145, the next column conductor output 99 changes to zero potential.

FIGURE 3c shows an alternate system for starting and resetting the matrix shown in 3a. This alternate system can be used in place of start circuit 147 and reset circuit 157. FIGURE 3c shows the system connected to the switching matrix in 3a but represented for sake of brevity as iip-ops 143 only, The system itself includes double and 210, playback relay switch 212 which may be located as part of the playback relay S7, FIGURE 2, and negative bias source 214. Each toggle switch shown is connected to its respective flip-flop 143 so that when the switch is in the upper position t-he negativebias from 214 is applied to the base of one transistor and when the switch is in the lower positio'nthel bias isl applied to the base of' the other transistor, in the Hiphop. The transistor receiving the negative bias is cut oit. Therefore, with the matrix connected as shown in 3a and with all toggle switches in the up position, vertical conductor 89 is forced to assume the on or zero volt condition. With toggle switch 202 in the down position the top iiip-fiop output .voltages are reversed wherein fvertical conductor 89 assumes the off or 12 volt condition and conductor 91 assumes the on or zero volt condition. If 204 only is moved to the lower position, third vertical conductor 93`assumes the on condition. If to the lower position, fifth conductor 97 assumes the on condition. If 208 only is moved to the lower position, ninth conductor 105 is actuated and if 210 only is moved, seventeenth conductor 121 is actuated. lIf more than one toggle switch is actuated, the switching effect is additive; that is, if, for instance, the fourth vertical conductor 95 is the desired starting point for the playback operation, toggle switches 202 and 204 are moved to the downward position.- The total biasing effect of these two switches causes their respective flip-ilops to, reverse their output conditions and by virtue of the conections 145, FIGURE 95 assumes the zero or on conthe sa-me as if start circuit cribe pen 13, FIGURE l, transcribe position',

147 were used.l After transis indexed over the proper playback relay 212, FIGURE 3c, is

' actuated placing equal bias on the base of each transistor connected directly to a conventional relay such as 212 in the bias circuit. This connection to relay 212 can be made throughl a conventional transistor switcln and therefore, is not shown for purposes of brevity, When the zero volt condition is applied to the stop plug, relay The operation of lcircuit 139 connected to 95 is is placed in the onr condition. With the system shown in 3c, stop plug 39 is 206 only is moved 212 is opened causing the matrix to clear to the vertical conductor selected by the actuated toggle switch as described above.

Refer now to FIGURE l4 for a brief study of the operation of circuit 139 which is the same regardless of whether start system 147, FIGURE 3a, or start system in FIGURE 3c, is used. vAfter the matrix has been cleared and the preselected column output, i.e., v97in FIGURE 3, is in the zero or on condition, this zero potential is applied to the base of .transistor 171, FIG- URE 4, connected to column conductor 97 in FIGURE 3. The zero potential causes 171 to cut off, allowing current to iiow from the positive 12 volt diode 179 and thus decrease the impedance of this diode to the signal from its associated magnetic head 9 in circuit 139. Zero voltage on the transistor base also allows current to flow through diode 185 and the chain of appropriately graduated resistors 183 to control circuit3. It should be noted here that eaoh resistor 183 is graduated in s-u'ch a manner that the total resistance oifered applies a different current to the control cricuit 3 depending on which circuit 139 is activated. This difference in current, as described heretofore, is applied to vthe control circuit producing the command voltage to position transcribing pen 13, FIGURE 1. It should also be noted that while the column conductor 97 output is in the zero volt condition, lall other column conductor outputs, FIGURE 3, are in a positivevolt condition. That is, all are positive but are not necessarily at the same value of positive voltage. The positive voltage causes the remaining transistors 171, FIGURE 4, to conduct to saturation, thus cutting off their respective diodes 179 thereby blocking the outputs from recording heads 9 and cutting off their respective diodesv 185 thereby preventing current from flowing into control circuit 3. Modulator M represents the portion of the circuit connected to head 9 that is not important to the inventive concept.

For a complete summary of operations, refer now to g FIGURES 3 and 4. Assuming again for purposes of channels of previously re- 7, FIGURE 1, are notdeand reset circuit 157 are to in the receptacle 33 located the receptacle 33 that is located in the circuit 97 that is yin control circuit 3, FIGURE turned on, cascaded flip-flops 143 are reset to their cleared l controlcircuit 3, FIGURE 4,

circuit 147 through patch plug 35,

connected to the column width is set on potentiometer 189, thev desired center gap width on potentiometer 191, and the desired edge gap width on potentiometer 193, all of which are located 4. When the equipment is position, as described above. Tha-t is, the ipdlops are cleared by gate 153 in start circuitv147, allowing the 400 cycle signal from 155 to `be applied to the input of the cascaded iiip-fop until the output of column'conductor 97 reaches the unique zero volt condition. As the ip-ops are pulsed and the zero output condition moves from` column conductor 89 toward FIGURE l, is indexed over its nels by virtue of the command 137, transcribed pen 13, respective transcribe chanto pen index 5, FIGURE 1. When the zero potential condition is applied to start gate 153 is closed, thus maintaining the output of column conductor 97 in the zero condition for one drum revolution. As described above, the on condition of 97 causes the transistor 171 in circuit 139, FIGURE 4, to cut ol and its diode 179 t0 conduct, thus allowing the signal voltage from the magnetic reading head 9 to pass through diode 179 through detector 11 to transcribe pen amplifier 15 and to transcribe pen 13, FIGURE l. The signal read by the magnetic source 187 through conductor that succeeds the lastL channel desired to be replayed. The desired transcribe voltages being sent through head 9, FIGURE 4, is transcribed to pen 13, FIGURE l,

during a single drum rotation, after which pen shift ramp switch 31'on recording drum 17, FIGURE l, sends a negative 24 volt pulse to the input of the-cascaded flipflops 143. This pulse actuates the flip-flops so that the unique zero output is moved from column 97 to 9.9, as

described above. With the application ofthe zero potential to the base of the transistor -connected to the column conductor 99 the recording and pen positioning cycle is repeated as described above. The transcribe and pen shift cycle is repeated until the column conductor in f which the stop plug`39 is inserted is reached. The stop plug isinserted in the receptacle 33 connected to circuit 139 following the last column conductor to be activated.

' At that time, the zero potential on reset circuit 157 produces a 12- volt pulse at output 165. By virtue of circuit 157 s parallel connections 167 to each flip-flop 143, the reset pulse-resets all flip-flops 143 as described above so 'i that their upper'output is zero volts and their lower output is +12 volts.

' Pen .indexing system The pen indexing device S, .FIGURE l, is designed to position playback Apen 13 over the-appropriate transcribe channel on drum 17, as directed by the'playba'ck switching matrix'a'nd control circuit 3. The typeof c'ontrol circuit vuseddepends o n the type of indexing device utilized. If it is desirable to use a servo-driven indexing l device, a `control circuit, such asfshownv in FIGURE 2 or 4, can bel used to develop a command voltage to ,vbperate the pen index. `As will be detailed hereinafter, the command voltagecan -be used to operate the servo in novel cuit isrrnoditie'd accordingly." Thenovelpen indexing mechanisms to be described hereinafter are not limited an office computerwith equal accuracy. In addition,1they was operated by a conventional error voltage and rotated `the lead screw until the error voltage was zero. It is well known that when such a servo mechanism is required to 'operate over a considerable linear distance the system loses much of. its accuracy. In fact, when a conventional servo indexing device is used 4to move a pen housing over a distance greater than 12 inches, the problem of inaccurately vlocated playback channels, etc., becomes serious. `Applicants novel invention has solved this. problem by developing pen,` indexing devices capable of operating over distances much greater than 12 inches and still retaining ahigh degree of accuracy in locating the playback channels.. Applicants vpen indexing devices, when 'operating overlong drums, utilize an incremental stepping system which retains the high degree of accuracy inherent in a vservo system operating over a few inches, and yet re- If f the pen incremental steps or the command voltage can be compared -witha second voltage to produce an errorV signal'to opcrate a conventional servo indexing system.

" indexing mechanism is not servo-driven, the' control cirin their operation andcan be used on a field recorder or i y are well suited for automatic, semiautomatic or manual 4duces the response time of such a system by a factor of I vtwo or three, depending on the'particular species used.

In addition to maintaining accuracy and reducing response time, applicants devices overcome the problems of jitter,

backlash, and servo-huntby the use of a novel brake and clutch arrangement.

While there have been disclosed herein several specific preferred embodiments of the present invention,

4various modifications, omissions kand reiinements which (b) a plurality of magnetic heads for converting the seismic information into counterpart electrical signalsl disposed above said rst drum, such that each said head is associated with one of said traces,

(c) a first multicontact switch for selecting individual ones of said traces for transcription arranged so vthat la separate one of its contacts makes electrical connection with each of said magnetic heads,

(d) a second rotatable drum having anassociated recording surface on which said selected traces individually transcribed in visual form, i (e) a transcribing pen movably mounted onv support means such that said pen is in recording relation with said second drum,

are

(f) apen indexingdevice for locating said transcribing y pen in predetermined recording positions relative to said second drum,

(g) a voltage source vto power said pen indexing device, and

(h) a second multicontact switch having the same number of contacts as said first switch and adapted to operate in unison therewith, which second-switch controls the voltage input to said pen indexing device through a resistor system. 2. A playback system in accordance with claim 1, wherein,l a third multicontact switch having the same number ofcontacts as said first and second switches con-. trols -andsynchronizes the switching actions of saidfirst and second switches. 3. A playback system in vaccordance with claim 2, whereiny an electrical pulse source activates said third switch each time said first drum completes a revolution. 4. A playback system for selecting and transcribing individual traces of a multitrace seismic magnetic record, comprising,

(a) a first rotatable drum adapted to receive said record, (b) a plurality of magneticheads for converting the seismic information into counterpart electrical signals disposed above said first drum such that each head is associated with one of said traces, (c) a first multicontact switch for selecting individual ones of said traces for transcription arranged so that a separate one of, its contacts makes electrical connection with each of said magnetic heads, (d) a second rotatable drum having an associated rev -cording surface on'which said selected traces are individually transcribed in visual form,

(e) a transcribing pen movably mounted on support means such that said pen is in recording relation with said second drum,

(f) a pen indexing device for locating said transcribing pen in predetermined recording positions relative to said second drum,

(g) a voltage source-to power said pen indexing device,

(h) a second multicontact switch having the same number of contacts as said tirst switch and including a resistor system for controlling the voltage output from said voltage source,

(i) a control unit connected to the l output of said l second switch for converting preset transcription instructions into proper command voltages for said pen indexing device,

(j) a third mu'ticontact switch having the same number of contacts as said first and second switches by the following I vof the transcribed and the width for controlling and synchronizing the switching actions of said first and second switches, and

(k) an electrical pulse source connected to said third switch, which pulse source emits a pulse which activates said third switch each time said first drum completes a revolution. l

5,. A playback system in accordance withclaim 4,

wherein the third switch has a'r'eceptacleassociated withv I each of its contacts and includes means suitable for con` nection therewith for selecting the traces to be transcribed anda center gap trace.

6. A playback system in accordance with claim 5, wherein said control unit includes a plurality of potentiometer's which develop voltagesto determine the width traces, the distance between the edge ofthe recording surface and the first transcribed trace,

and'duration of the center gap.

' 7. A playback ksystem for selecting and transcribing individual traces of a multitrace seismic magnetic record,

comprising,

converting preset transcription instructions into proper command voltages for said pen indexing device,

(m) a fourth multicontact switch having the same number of contacts as said first, second, and third switches for controlling and synchronizing the switching actions of said first, second, and third switches,

(n) a ramp switch connected lo said first drum in a manner such that said switch is energized each time y said first drum completes a revolution, and (o) a second voltage source connected to said fourth switch and to said ramp switch, which second voltage l source sends an electrical pulse to said fourth switch each time fsaid ramp switch is energized thereby causing said fourth switch to move one contact.

8. A playback system in accordance with claim 7, wherein said first, second, third, andifourth switches are ganged sequential switches such that each time said fourth switch moves one contact said first, second, and third switches move one contact.

9. A playback system in accordance with claim 8,

whereinsaid first, second, third, and fourth switches nclude an array of relay contacts connected to a plurality (e) a lsecond multicontact switch.v havingv the same v number of contacts as said first switch for receiving the output seismicsignals from said detector system, (f) apen amplifier connected to the output of said second switch for amplifying said seismic signals,

(g) a second rotatable drum having an associated recordingsurface on which said selected traces are inldividually transcribed in visual form, (h) a transcribing pen connected to the output of said pen amplifier and movably mounted on support means such that said pen is in recording relation with said second drum, v

(i) a pen indexing device for loca'ting said transcribing pen in predetermined recording positions relative to v v said lsecond drum,

(j) a first voltage source to power said pen indexing fdevice, y (k) `a third multicontact switch having the same number of contacts as said `first and second switches and including a resistor system for controlling the voltage output from said first'voltage source, (l) a control unit including a plurality of potentiometers connected to theA output of said third switch for of relays and divides.

10. A playback system in accordance with claim 8, wherein said first, second, land third switches include a plurality of transistors and said fourth switch includes an array of horizontal and vertical conductors interconnected in a predetermined manner and a plurality of binary counters connected to said horizontal conductors.

References Cited by the Examiner UNITED STATES PATENTS 1,480,734 1/24 Nelson 346-139 2,378,389 6/45 Begun 346-21 2,579,831 12/51 Keinath 346-33 2,606,808 8/52 Brown 346-33 2,626,979 1/53 Woods s- 324-1v 2,803,515 8/57 Begun'et al 346-33 2,876,428 3/59 Skelton et al. 340-155 2,926,984v 3/60 Gerbrands 346-139' 2,958,849 11/60 Begun 340-1725 2,975,399 3/61 Burns 340-155 2,976,107 3/61 Klein et al. 346-109 2,986,722 5/61 Williams 340-155 3,014,650 12/61 Skelton et al 23S-61.6 3,028,579 4/62 McCarter et al. 340-155 3,041,578 6/62 kElliott 340-155 3,046,553 7/62 Hawkins et al. 346-17 3,047,836 7/ 62 Johnson et al 340-155 3,048,847 8/ 62 Forst et al 346-1` 3,105,220 9/63 Groenendyke 340-155 vLEYLAND M. MARTIN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 210, 770 October 5, 1965 John P Woods et alc It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the drawings, sheets l to 4, lower right-hand corner strike out "William M. Mullings" and "James K. Lyons" each occurrence; column 2, line 71, for "palyback" read playback-; column 6, line 4, for "of" second occurrence, read or column 7, line 61, for "153", second occurrence, read 143 column 8 lines 6 and 7, strike out "One end of diode 179 is connected to the inputof detector 11."; line 38, for "divided" read divider column 10, line 62, for "transcribed" read transcribe column 13, line Z8, strike out "said", first occurrence; line 29, after "that" insert a Signed and sealed this 14th day of June 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer l Commissioner of Patents 

1. A PLAYBACK SYSTEM FOR SELECTING AND TRANSCRIBING INDIVIDUAL TRACES OF A MULTITRACE SEISMIC MAGNETIC RECORD, COMPRISING, (A) A FIRST ROTATABLE DRUM ADAPTED TO RECEIVE SAID RECORD, (B) A PLURALITY OF MAGNETIC HEADS FOR CONVERTING THE SEISMIC INFORMATION INTO COUNTERPART ELECTRICAL SIGNALS DISPOSED ABOVE SAID FIRST DRUM SUCH THAT EACH SAID HEAD IS ASSOCIATED WITH ONE OF SAID TRACES, (C) A FIRST MULTICONTACT SWITCH FOR SELECTING INDIVIDUAL ONES OF SAID TRACES FOR TRANSCRIPTION ARRANGED SO THAT A SEPARATE ONE OF ITS CONTACTS MAKES ELECTRICAL CONNECTION WITH EACH OF SAID MAGNETIC HEADS, (D) A SECOND ROTATABLE DRUM HAVING AN ASSOCIATED RECORDING SURFACE ON WHICH SAID SELECTED TRACES ARE INDIVIDUALLY TRANSCRIBED IN VISUAL FORM, (E) A TRANSCRIBING PEN MOVABLY MOUNTED ON SUPPORT MEANS SUCH THAT SAID PEN IS IN RECORDING RELATION WITH SAID SECOND DRUM, (F) A PEN INDEXING DEVICE FOR LOCATING SAID TRANSCRIBING 